It occurs because these stab entries refer to external symbols which never appear in the symbol table because they are never referenced inside the original program.

I noticed that ld on Ubuntu didn't report these errors.

Description

A simple helloworld.c program with stabs debugging will produce the following output:
can't find atom for N_GSYM stabs ___stdinp:G15=*1 in /tmp/ctm.TKZ8PQ
can't find atom for N_GSYM stabs ___stdoutp:G15 in /tmp/ctm.TKZ8PQ
can't find atom for N_GSYM stabs ___stderrp:G15 in /tmp/ctm.TKZ8PQ
can't find atom for N_GSYM stabs _sys_nerr:G1 in /tmp/ctm.TKZ8PQ
can't find atom for N_GSYM stabs _sys_errlist:G16=ar1;0;-10202;17=*2 in /tmp/ctm.TKZ8PQ
It occurs because these stab entries refer to external symbols which never appear in the symbol table because they are never referenced inside the original program.
I noticed that ld on Ubuntu didn't report these errors.